Door construction



Dec. 1, 1953 J. c. PETTERSON DOOR CONSTRUCTION Filed May 25, 1949 vINVEHTOQ, JOHN G DETTEIQSON ATTOQNEY Patented Dec. 1, 1953 UNITED STATESPATENT OFFICE 2 Claims.

The present invention relates broadly to doors and more specifically tothat type of construction ordinarily known as a flush door. Flush doorscontemplate the use of plywood panels for both sides of the door withrails and stiles interposed between the said panels. The panels usuallyare secured. to the rails and stiles by gluing. As a rule, the averagehollow core flush door construction does not permit the uninhibited useof hardware, such as locks, catches and the like, and the flush doorsoften sag or warp.

An object of the present invention is the provision of a door of theflush type which permits the hanging of the door from either side.

A further object is the provision of a door of the character statedwherein strength is combined with lightness of weight.

A further object is a door which may be easily fabricated, thuseffecting a saving in cost of manufacture.

With the above mentioned and other objects in view, the inventionconsists in the novel and useful provision, formation, construction,association and relative arrangement of parts, members and features, allas shown in one embodiment in the accompanying drawing, describedgenerally and more particularly pointed out in the claims.

In the drawings;

Figure 1 is a fragmentary front elevation of a door incorporating theinvention;

Figure 2 is a fragmentary sectional view on the line 2-2 of Figure 1;and

Figure 3 is a perspective view of one of the truss ribs for the door ofthe invention.

Referring now with particularity to the drawing, I have shown a door ofthe flush type which includes a pair of spaced apart and substantiallyparallel stiles i and 2 secured to top and bottom rails 3. The stilesand rails may be held together in any suitable manner, such as by thesinuous nails 4, or by other means. While the stiles and rails may beformed of single pieces of wood or other material, I have found itexpedient in certain constructions to form a built up structure ofblocks laid in break-joint or other relationship and secured together bywater-proof glue, as indicated for the stile 2 at 5. Such a constructionfor the stiles and rails effectively prevents warpage.

Assuming that the stiles and rails are interconnected, as illustrated inFigure 1, I then provide a core for the door comprising a trussstructure designated generally as 6. The truss structure is adapted toprevent door sag, while providing a light, strong construction having asmooth face on the finished door. In order to fabricate the trussstructure, one of the facing panels, such as the panel 8, is secured byglue to the stiles and rails after which the truss struc ture is placedin position. The truss structure illustrated is of the lattice type.

In Figure 3, one of the ribs 9 of the truss structure is shown and theedges thereof are notched, as shown at H) and II. The notches arestaggered, and in the present instance, only two notches are provided,although any multiplenumber thereof may be provided in a rib. The ribsare laid on edge between the stiles and against the inner surface of thepanel 8. The arrangement is such that ribs intersect at the notchedzones so that the edges of the ribs lie in single planes. In otherwords, each notch is substantially one-half the depth or width of a rib.The edges of the ribs are water-proof glued to the inner surface of thepanel 8. Preferably, I do not glue ends of the ribs to the stiles nor tothe rails.

To obtain maximum strength combined with lightness of construction, theribs intersect or cross at thirds or quarter points of their length, andin the drawing, the ribs are shown intersecting or crossing at thirdpoints. I prefer this construction over a construction wherein the ribsintersect at center points, as I obtain greater flexibility, and theribs remain in place during fabrication of the core.

After the ribs have been assembled for the complete door length, thestiles and rails, together with the opposite edges of the ribs, arecovered with water proof glue, followed by placing a panel 12 thereover,and the completed door is then placed in a press and held therein for asufficient length of time to assure proper securing of the parts inworking relationship. The particular type of glue used, the character ofthe press, and whether it is either a cold or a radiant heat operation,forms no part of the invention.

Preferably, the stiles are of considerable width as are likewise, therails, and not less than four and one-half inches in width. This permitshardware to be secured to the door, a factor of importance. I alsoprovide full length edging strips It on both vertical edges of thestiles to give finish to the door.

The operation, uses and advantages of the invention are, as follows:

It will be observed upon reference to Figure 1 that each rib forms aside for at least two quadrihave face panels of any wood desired, thatis, a

hard wood or a soft wood, depending upon use for the door. I claim:

1. A hollow core flush door of the type having two opposite sides ofplywood panels, a frame formed of parallel stiles connected by a toprail and a bottom rail, with a multicellular construction between thepanels inside of the frame; in which the multicellular constructionforms a lattice-truss core and is composed of identical ribs each astraight strip of uniform width and thickness with one notch in one edgeand a similar laterally spaced notch in the opposite edge, the width ofeach notch being sufdciently great in proportion to the thickness of thestrip to permit each of the strips when assembled as a truss to make achosen angle with horizontal down to as little as fifteen degrees, thusforming horizontally positioned lozenge-shaped quadrilateral cells aboutfour times as wide as high, the notch intersections providing freeaccess of air to all of the cells, thus avoiding the necessity forperforations in the strips between the intersections, while presentingall edges of the strips in planes corresponding to the inside surfacesof the two panels.

2. The door of claim 1 in which the strips terminate short of contactwith the frame, are firmly secured to the panels at opposite edges ofthe strips, the two notches of each strip are at equal distance from therespective proximate end of the strip, the intersections are offset fromthe vertical centerline of the door and are nearer said centerline thanto the inner side of the proximate stile, whereby to give strength andrigidity to the door about equal to that of a solid door but having onlyabout half the weight of such send door.

JOHN C. PETTERSQN.

References Cited in the file of this patent UNITED STATES PATENTS

